We are happy that there are replacements because we need them. Like the other reviewer, my almost 2-year old goes through them quickly. She bites it as soon as we put in a new one, which makes it leaks a lot. My 3 1/2-year old son does much better but his still leaks eventually.

I have to say we've had success cleaning it with the brush kit. But we have to do it weekly to avoid the mold.

Love the bottle, my toddler has used it everyday for the past 6 months. Problem: i noticed that the bite valve becomes mouldy due to baby backwash and once its mouldy its really difficult to clean, eve with a small bottle brush. The vave is also rather leaky, if te bottle lies on its side it drips.